ES2439792T3 - Semi-constrained anchoring system - Google Patents

Abstract

A spine bar anchoring system (10) comprising: a bar (12) adapted to extend along a spine of a patient; and a bar anchor (14B) adapted to be fixed to a vertebra of the spine, the bar anchor (14B) adapted to accommodate the bar (12) so that the bar (12) is fixed against substantial lateral translation relative to the bar anchor (14B), characterized in that the bar (12) is allowed to slide axially with respect to the bar anchor (14B) through a pivot point (P2) and change pitch and deguiñada around the pivot point (P2) while substantially warping the bar (12) with respect to the bar anchor (14B).

Description

Semi-constrained anchoring system

5 Background

Many systems have been used to treat spinal deformities such as scoliosis, spondylolisthesis and various other deformities. Primary surgical methods to correct a spinal deformity use instrumentation to correct the deformity as much as possible, as well as implantable physical support systems to rigidly stabilize and maintain correction. Currently, most of these implantable physical support systems rigidly fix the spine or allow for limited growth and / or other movement of the spine, to help facilitate fusion after the spine has moved to a position. corrected

15 US 2009/012565 A1 refers to a system for correcting a deformity of the spine that includes an implant attached to one side of a vertebra and a bar that extends along an axis of the spine in a Second side of the vertebra. An adjustment member, which may include a reel, is attached to the bar. A force steering member, such as a cable, extends between the bar and the adjustment member. The force steering member is retractable to and extendable from the adjustment member. A method of correcting a spinal deformity includes providing an implant, a bar, an adjustment member coupled to the bar, and a force steering member that extends between the bar and the adjustment member. The adjustment member can be retractable to and extendable from the adjustment member.

WO 2008/086467 A2 refers to a fixing system that is designed to block a member

Elongated within a housing member, allowing positional and / or orientation adjustment of the elongated member before locking. The system includes a carcass member, a spherical spherical collar, an elongated member, and can include a gradually narrowed wedge, which can be a discrete component or be formed as part of the elongated member. The housing member and / or the elongated member may be implantable. The elongated member may be placed in the wedge, the wedge in the collar, and the collar in the housing so that, when compression force is applied to the wedge and the collar, the wedge contracts around the elongated member and the collar it expands to engage with the housing, thereby blocking the elongated member with respect to the housing. The collar may have a gradually narrowed channel with a degree of gradual narrowing equal to that of the gradually narrowed wedge. The collar can have multiple grooves to allow uniform radial expansion and compression.

35 US 2004/215190 A1 refers to systems and methods for aligning and implanting orthopedic fixation or stabilization implants within the body. In one embodiment, the system includes at least two bone anchors, of which at least one is provided with an angularly adjustable connector. In one aspect, the system also includes at least one connecting rod, to connect two or more bone anchors through their respective adjustable connectors. Bone anchors and connecting bar can be locked in place to form a fusion or spinal fixation prosthesis. An alignment tool is provided, to guide a guidewire through one or more connectors.

Summary

The present invention is characterized by a backbone anchoring system comprising the elements of claim 1. Preferred embodiments of this system are defined in the dependent claims.

The embodiments refer to systems for correcting spinal deformities that help minimize a series of binding anchors used for correction, facilitate the use of straight or contoured bars, and / or help promote a more natural physiological movement of the spine. vertebral

The embodiments relate to a system for correcting a spinal deformity between a first vertebra and a second vertebra of a person's spine, where the system includes a bar

55 substantially rigid adapted to extend by deformity of the spine. The system also includes a first bar anchor adapted to be fixed to the first vertebra and to accommodate a first end of the bar so that the bar is allowed to move axially with respect to the first bar anchor, as well as a second bar anchor bar adapted to be fixed to the second vertebra and to accommodate a second end of the bar. A first force steering member is coupled between the bar and the deformity of the spine, where the first and second bar anchors are adapted to resist lateral translation of the bar with respect to the spine and to allow an axis Longitudinal of the bar change from at least one pitch and one yaw.

Some embodiments relate to exerting a strain and / or compression force on a spine

65 fixing first and second bar anchors on a first side of the spine. First and second parts of a bar are housed in the first and second bar anchors, respectively, so that the first and second parts are substantially constrained against lateral translation. The first and second parts are capable of changing pitch and yaw in the first and second bar anchors, respectively, in response to the movement of the spine. First and second stops are located adjacent to the first bar anchor and the second bar anchor, respectively. The first side of the spine is distended and / or compressed

5 imposing a force on the bar with the first and second stops.

Although multiple embodiments are disclosed herein, further embodiments of the present invention will become apparent to those skilled in the art from the following detailed description, which shows and describes illustrative embodiments of the invention. Therefore, the drawings and detailed description should be considered illustrative and not restrictive in nature.

Brief description of the drawings

Figure 1 shows an exemplary system for correcting a deformity of the spine, according to some embodiments.

Figure 2 is a bottom view of the system of Figure 1 with some elements not shown for ease of understanding, in accordance with some embodiments.

Figure 3 shows a bar of the system of Figure 1, according to some embodiments.

Figure 4 shows another bar of the system of Figure 1, according to some embodiments.

Figures 5a, 5b and 6 show elements of an anchor of the system of Figure 1, in accordance with some embodiments.

Figures 7 and 8 show elements of another anchor of the system of Figure 1, in accordance with some embodiments.

Figures 9-11 show another anchor of the system of Figure 1, according to some embodiments.

Figure 12 shows alternative complementary ways to limit warping between preselected angular limits, according to some embodiments.

Figure 13 shows a vertebral anchor and a first force steering member of the system of Figure 1, according to some embodiments.

Figures 14a and 14b show an adjustment mechanism of the system of Figure 1, in accordance with some embodiments.

Figures 15a, 15b and 15c show some stop elements of the system of Figure 1, according to some embodiments.

Figure 16 is a schematic view showing some of the degrees of freedom of the system of Figure 1, in accordance with some embodiments.

Figure 17 is another schematic view showing some other degrees of freedom of the system of Figure 1, in accordance with some embodiments.

Figures 18 and 19 are other schematic views showing degrees of freedom of axial translation, according to some embodiments.

Various embodiments have been shown by way of example in the drawings and are described in detail below. As indicated above, the intention, however, is not to limit the invention by providing such examples.

Detailed description

The embodiments refer to a system for correcting deformities of the spine. In general terms, the system provides lateral translation corrective force or forces and / or rotational corrective forces or forces on a spine. Some elements of the system include highly adaptive physical support to connect the system to the spine, where the physical support facilitates a more natural range of movement within preselected limits and the application of such lateral and / or rotational translational corrective forces or forces.

65 In the following description reference is made to various planes and associated directions, including a sagittal plane defined by two axes, one drawn between a head (upper) and a caudal part (lower) of the body and one

tracing between a rear (rear) and a front (anterior) part of the body; a coronal plane defined by two axes, one drawn between a center (medial) and a side (side) of the body and one drawn between a head (upper) and a caudal part (lower) of the body; and a transverse plane defined by two axes, one drawn between a rear part and a front part of the body and one drawn between a center and a side of the body. The terms 5 pitching, warping and yaw are also used, where warping generally refers to angulation, or rotation, in a foreground through which a longitudinal axis of a body passes orthogonally (e.g., rotation around an axis longitudinal corresponding to the spine), pitching refers to angulation, or rotation, in a second plane orthogonal to the foreground, and yawning refers to angulation, or rotation, in a third plane orthogonal to the first and second planes. In some embodiments, pitching is angulation in the sagittal plane,

10 yaw is angulation in the coronal plane and warping is angulation in the transverse plane.

In various embodiments, pitching, yaw and / or warping changes occur concurrently or separately, as desired. In addition, as used herein, "lateral translation" is not limited to translation in the medial-lateral direction unless specified as such.

15 Figure 1 is a perspective view of a system 10 for correcting a deformity of the spine, according to some embodiments. System 10 includes a bar 12, a plurality of bar anchors 14, including a first bar anchor 14A and a second bar anchor 14B, a plurality of vertebral anchors 18 including a first vertebral anchor 18A and a second vertebral anchor 18B, a plurality of

20 adjustment mechanisms 20 including a first adjustment mechanism 20A and a second adjustment mechanism 20B, and a plurality of force steering members 22 including a first force steering member 22A and a second force steering member 22B. As shown, the system 10 is fixed to a spine 24 formed by a plurality of vertebrae 26, including a first vertebra 26A, a second vertebra 26B, a third vertebra 26C and a fourth vertebra 26D.

25 Although the system 10 is shown with two bar anchors 14, two vertebral anchors 18, two adjustment mechanisms 20 and two force steering members 22, they are more or less implemented as appropriate. For example, in some embodiments a single vertebral anchor 18 is fixed to a vertebra 26 at an apex of a spinal deformation and other location, with a corresponding force steering member 22 and a

30 adjustment mechanism 20 coupled to said vertebral anchor 18.

As shown in Figure 1, however, the first and second vertebral anchors 18A, 18B are fixed to a part of the spine 24 that has an abnormal curvature (eg, scoliosis) that needs correction. The system 10 is optionally used to gradually bring the spine 24 to a curvature.

35 more natural, or a single adjustment is made to system 10 to achieve the desired curvature. In other embodiments, an abnormal curvature in the spine 24 has been adjusted to a more natural curvature using another support system, before or next to the fixation of the system 10 to the spine 24.

Figure 2 shows the system 10 from a cross-sectional view, with parts of the spine 24 and the

40 system 10 not shown for illustrative purposes. For reference, the bar 12, the first vertebral anchor 18A, the first adjustment mechanism 20A and the first force steering member 22A are shown together with the first vertebra 26A and the third vertebra 26C.

In some embodiments, bar 12, also described as an elongated member, is fixed to the column.

45 vertebral 24 at a preselected deviation from a longitudinal axis of the spine 24. For example, the bar 12 is optionally fixed at a deviation along a medial-lateral axis ML, or axis from right to left, and a AP antero-posterior axis, or postero-frontal axis. In some embodiments, the bar 12 is fixed on the left side of the spine 24. As described below, the offset is optionally selected to cause at least one relative lateral translation (eg, central movement or

50) and rotational displacement (for example, clockwise rotation from the bottom view of Figure 2) of selected vertebrae 26 of the spine 24 (relative antero-posterior movement of the selected vertebrae can also be achieved 26) so that the spine 24 shows a more natural position.

55 Figure 3 shows the bar 12 having a curvature according to some embodiments. In some embodiments, the bar 12 is substantially rigid, defining a substantially round cross section with an average diameter of approximately 6 mm and which is formed by a suitable biocompatible material, such as ASTM F136 titanium alloy. The bar 12 is adapted, or structured in another way, to extend along the spine 24. In Figure 1, the curvature of the bar 12 is generally shown for purposes

60 illustrative. In various embodiments, the bar 12 is bent in one or more of the sagittal and coronal planes. If desired, the bar 12 incorporates some flexibility or elasticity while substantially retaining its shape in a rigid manner. The bar 12 is optionally formed of various materials, including stainless steel or suitable polymeric materials. In addition, as described below, the cross-sectional shape of the bar 12, including various parts thereof, is not limited to circular cross-sections.

65 As shown in Figure 3, in some embodiments, the bar 12 is contoured or angled to at least partially mimic a curvature (for example, kyphosis or lordosis of the sagittal plane or, alternatively, an existing defective curvature, by example, kyphosis or lordosis) of a part of a spine. Although shown with a single curvature, so that the bar 12 is substantially non-linear, in other embodiments the

5 bar 12 includes substantially curved non-linear sections, or incorporates combinations of substantially bent, straight and / or curved sections.

The bar 12 has a longitudinal axis X, as well as a first section 30, a second section 32 and an intermediate section 34 between the first and second sections 30, 32. Where the bar 12 is substantially straight, the longitudinal axis X is substantially straight . Where the bar 12 is substantially curved or angled, the longitudinal axis X is curved or angled analogously. Sections 30, 32, 34 of bar 12 are optionally formed continuously or are formed as different parts, connected as desired. In some embodiments, the second section 32 and the intermediate section 34 define an internal angle Ia less than 180 degrees, for example a curvature angle of about 135 to about 170 degrees, although

15 contemplate different angles of curvature.

In some embodiments, at least one or both of the first and second sections 30, 32 are generally non-round or otherwise define advance elements. For example, as shown in Figures 3 and 4, the second section 32 forms at least one flat surface 36, the second section 32 having a substantially D-shaped cross section along at least a portion thereof. . In turn, the first section 30 and the intermediate section 34 have substantially circular cross sections, although any of the sections 30, 32, 34 optionally have non-circular cross-section shapes, as desired (e.g., star-shaped cross sections , oval, or square). As will be described later, a cross-sectional shape of a particular section is optionally used to limit the rotation of the bar 12,

25 although cross-sectional modifications are also contemplated to selectively improve the bending performance and other characteristics of the bar 12 (for example double T profile, hexagonal or other shapes).

At least some of the intermediate section 34 optionally includes a surface treatment, such as surface removal 38 (e.g. knurling or inlay), or other treatment (eg, coatings, plasma treatments, or others) to improve friction and / or performance. In turn, parts of the first and second sections 30, 32 optionally include specular finishes, surface coatings (eg, PTFE), or other materials or surface treatments. Although some examples have been provided, various combinations of surface treatments are contemplated for parts of each of sections 30, 32,

35 34.

Figure 4 shows a bar 12A according to some more embodiments. The bar 12A is substantially straight, or linear, and includes any of the elements described together with the bar 12 as appropriate. In Figure 4 the elements of the bar 12A similar to those of the bar 12 are designated with the same reference number as the bar 12 followed by an "A".

In some embodiments, the bar 12A is of a two-piece design and includes a bar adjustment mechanism 39 that provides means for increasing an effective length of the bar 12A. The bar adjustment mechanism 39 is optionally a female threaded sleeve adapted to extend or contract (lengthen or shorten) a space

45 between parts of the bar 12A converting the adjustment mechanism 39 into gear threads 37 in the sleeve. The adjustment mechanism 39 optionally has flat surfaces or other surface elements to accommodate a tool (for example, an open end wrench). An example of another female sleeve type adjustment mechanism generally suitable for use with some embodiments described herein is shown in US Patent No. 4,078,559, issued March 14, 1978.

Additional examples of bars according to some embodiments of system 10 are described in US Application No. 11 / 196,952, filed on August 3, 2005 (Publication No. US 2006/036246 A1) and entitled DEVICE AND METHOD FOR CORRECTING A SPINAL DEFORMITY , as well as 12 / 134,058, filed on June 5, 2008 (Publication No. US 2009/012565 A1) and entitled MEDICAL DEVICE AND METHOD TO CORRECT

55 DEFORMITY.

Figures 5a and 5b show elements of the first bar anchor 14A, according to some embodiments. As shown in Figure 5a, the first bar anchor 14A is adapted, or structured in another way, to be mounted, or fixed to one or more vertebrae, such as the first vertebra 26A (Figure 1). The first bar anchor 14A is further adapted to accommodate, and includes means for housing, the bar 12 so that the bar 12 is fixed laterally, against the lateral translation with respect to the first bar anchor 14A. In some embodiments, the bar 12 is substantially prevented from moving in a direction substantially perpendicular to the longitudinal axis X at the first point P1. In turn, the bar 12 (shown in section) is capable of sliding axially, or moving axially, along the longitudinal axis X, with respect to the first anchor of

65 bar 14A through a first pivot point P1. The bar 12 is also capable of changing pitch, yaw and warping around the first pivot point P1.

The first bar anchor 14A is optionally formed by biocompatible metal materials, such as titanium, stainless steel and / or biocompatible polymeric materials, such as PEEK and / or composite materials. In some embodiments, and as shown in Figures 5a, the first rod anchor 14A includes a single piece housing 40 having a receptacle part 48 adapted, or structured in another way, to accommodate the

5 bar 12. The first bar anchor 14A further includes a mounting portion 50 adapted to fix the first bar anchor 14A to one or more vertebrae, such as the first vertebra 26A and an additional vertebra 26 above or below the First vertebra In other embodiments, the mounting part 50 is fixed to a single vertebra, such as the first vertebra 26A (for example, laterally through the first vertebra 26A in the pedicles, or at a single point - such as a single pedicle - in the first vertebra 26A.

As described below, in some embodiments, the housing 40 is of a multi-piece design (for example, as shown in Figures 7-11).

In some embodiments, the mounting part 50, also described as a plate, is adapted to be fixed in

15 two or more points, for example extending between two vertebrae (for example, the L3-L4 vertebrae) or extending through a part of a single vertebra (for example, from pedicle to pedicle in a single vertebra).

Figure 5b shows the receptacle part 48 in cross section. According to various embodiments, the receptacle part 48 is generally ring-shaped and forms a passage 52 having a rotating convex surface 54 having an upper curve 56 and a lower curve 58. The receptacle part 48 is adapted to allow the bar 12 passes through the passage 52 at the first pivot point P1, where the passage 52 defines a minimum effective diameter (for example, providing an appropriate clearance between the bar 12 and the receptacle part 48) that allows the bar 12 slides through the passage 52. The passage 52 also allows the bar 12 to rotate and anchor around the longitudinal axis X at the first pivot point P1 while minimizing

25 lateral translation or inhibits substantial lateral translation. At least in this way, the bar 12 is able to rotate and angle around the longitudinal axis X at the first pivot point while the lateral translation of the bar 12 with respect to the receptacle part 28 is substantially limited in all planes. In alternative terms, the bar 12 is able to slide into the passage 52 and change yaw, pitch and warp at the first pivot point P1, while being constrained against the movement from side to side within the passage 52 at the first point of P1 pivot.

In some embodiments, the mounting part 50 includes a rod 60 and a pedestal 62, the pedestal 62 having a central part 64, a first anchor point 66, and a second anchor point 68, the central part 64 extending between the first and second anchor points 66, 68 and each of the anchor points 66, 68 defining

35 a surface suitable for mounting the first bar anchor 14A on one or more vertebrae 26. The first and second anchor points 66, 68 optionally include through holes 70, 72, respectively, to accommodate a fixator (not shown), such as a pedicle screw or similar device to fix the mounting part 50 to one or more vertebrae 26, such as the first vertebra 26A (Figure 1).

In some embodiments, the first bar anchor 14A is adapted, or structured in another way, to limit the pitch and yaw of the bar 12 to a predefined interval. For example, the bar 12 is able to angle at an interval until opposite surfaces of the bar 12, contact, or join with the upper and lower curves 56, 58 of the convex surface 54. In other words, a radius of curvature. of the convex surface 54 is optionally selected to control a range of motion of the bar 12. In some embodiments, the pitch and the

The yaw of the bar 12 is limited to within an angular range Ra of approximately 60 degrees, for example. As described below together with the second bar anchor 14B, various means are also contemplated to limit the warping and / or sliding of the bar 12 within a predefined range.

Although in some embodiments the mounting part 50 is adapted to accommodate one or more fasteners as shown in Figures 5a and 5b, Figure 6 shows the first bar anchor 14A with the mounting part 50 being adapted to act as a fixator, similar to a pedicle screw. Thus, the first bar anchor 14a optionally includes fixing means for fixing the first anchor 14A to one of the vertebrae 26.

Although Figures 5a, 5b and 6 are illustrative of some potential elements of the system 10, Figures 7 and 8

55 show a first bar anchor 114A according to some other embodiments, wherein Figure 7 is a perspective view with the bar 12 housed in the first bar anchor 114A and Figure 8 is a cross-sectional view of the first anchor of bar 114A with bar 12 removed. The first rod anchor 114A is substantially similar to the first rod anchor 14A, although a housing 140 of the first rod anchor 114A includes a receptacle part 148A and a sleeve portion 148B. In some embodiments, the sleeve portion 148B is substantially spherical in shape and the receptacle portion 148A forms a substantially spherical engagement track for the sleeve portion 148B.

As shown in Figure 8, the receptacle part 148A has a substantially concave rotating surface 154A and the sleeve portion 148B has a substantially convex rotating surface 154B. The surfaces 154A, 154B are adapted, or structured in another way, to form a substantially complementary fit to each other, so that the sleeve part 148B is captured by the receptacle part 148A and

the relative rotational and angular movement with respect to the receptacle part 148A is allowed.

The sleeve part 148B has a passage 152 defining a pivot point P11 through which the bar 12 is capable of being housed so that it can slide. As with other embodiments, the relationship

5 complementary between the sleeve part 148B and the receptacle part 148A is optionally designed to restrict, or limit, certain relative movement of the bar 12 with respect to the first bar anchor 114A. For example, in some embodiments, the pitch and yaw of the bar 12 around the pivot point P11 are limited when opposite surfaces of the bar 12 contact the receptacle part 148A near a front part 156 and / or a rear part 158 of receptacle part 148A.

Figure 9 is a perspective view of the second bar anchor 14B and Figures 10 and 11 are perspective views of parts thereof. The second bar anchor 14B is adapted to be fixed, and provides means for fixing to a second vertebra, such as a second vertebra 26B (Figure 1). The second bar anchor 14B is further adapted to accommodate, and provides means to accommodate, the bar 12 (Figure 1) so that

15 the second bar anchor 14B limits the translational movement of the bar 12 except along the longitudinal axis X and allows the bar 12 to change at least pitch and yaw around a second pivot point P2. The second bar anchor 14B is optionally substantially similar to the first bar anchor 14A or the first bar anchor 114A, including any desired combination of elements described above.

The second bar anchor 14B is optionally formed by biocompatible metal materials, such as titanium or stainless steel and / or biocompatible polymeric materials, such as PEEK. In some embodiments, and as shown in Figure 9, the second bar anchor 14B includes a housing 200 having a receptacle part 202 and a sleeve part 204 adapted to accommodate the bar 12, further including the second

25 bar anchor 14B a mounting part (for example, similar to the mounting part 50 of the first bar anchor 14A) adapted to fix the second bar anchor 14B to the second vertebra 26B.

The second bar anchor 14B is optionally adapted, or structured in another way, to limit the rotation, or warping, of the bar 12 around the longitudinal axis X of the bar 12 (Figure 3). In particular, the second bar anchor 14B provides means to allow the bar 12 to be anchored without substantial lateral translation with respect to the second bar anchor 14B or substantial rotation around the longitudinal axis X. The sleeve portion 204 is optionally spherical in shape. and the receptacle part 202 forms a substantially spherical coupling track, where the rotation of the sleeve part 204 with respect to the receptacle part 202 is substantially inhibited in at least one plane.

Figure 10 shows the receptacle part 202 and Figure 11 shows the sleeve part 204, where the receptacle part 202 has a substantially concave, rotating inner surface 210 and the sleeve part 204 has a substantially convex, rotatable outer surface 212. The surfaces 210, 212 are adapted to form a substantially complementary fit with each other, so that the sleeve part 204 is captured by the receptacle part 202 and is allowed relative angular movement with respect to the receptacle part

202.

As shown in Figure 10, the receptacle part 202 also includes a pair of protrusions 216 (eg, pins), which extend inwardly from and on opposite sides of the inner surface 210. In turn,

45 as shown in Figure 11, the sleeve part 204 has a circumferential groove 218 adapted to accommodate so that they can slide to the protuberances 216 and an internal passage 220 through which the bar 12 can be accommodated so that it can to slide. A pivot point P2 is also defined in the passage 220, the bar 12 passing through the pivot point P2.

The passage 220 optionally has a non-circular cross section (for example, a substantially D-shaped cross section corresponding to the second section 32 of the bar 12). At the time of coupling of the non-circular cross sections of the bar 12 and the passage 220, the rotation of the bar 12 with respect to the sleeve portion 204 is substantially inhibited.

55 At the time of accommodation, so that they can slide, from the protuberances 216 in the circumferential groove 218 the pitch and yaw of the bar 12 are capable of changing. The relative rotation between sleeve part 204 and receptacle part 202, however, is substantially inhibited. Therefore, since the relative rotation between the sleeve part 204 and the receptacle part 202 is also substantially inhibited, the relative rotation between the bar 12 and the second bar anchor 14B is inhibited or substantially limited, allowing the bar 12 is maintained in a preselected rotational position with respect to the second bar anchor 14B. It should also be understood that other cross-sectional shapes for each of the passage 220 and the bar 12 may be selected to allow some degree of rotation about the longitudinal axis X within a predefined range, including, for example, that shown in Figure 12, where the bar 12 is shown with elements that allow rotation up to a stop 220A formed by the sleeve 204. The section shape

The cross section of the bar 12 is also optionally selected to limit the axial translation of the bar 12 as desired.

As with other embodiments, the second bar anchor 14B is also optionally adapted to restrict, or limit the angulation of the bar 12 (eg, pitch and yaw) with respect to the second bar anchor 14B. For example, the pitch and yaw of the bar 12 around the pivot point P2 are limited when the bar 12 contacts the receptacle part 202 near a front part 222 and / or a

5 rear portion 224 of the receptacle part 202. A size and shape of the receptacle and / or sleeve portions 202, 204 are selected to define said limit or limits as desired.

Figure 13 shows the first vertebral anchor 18A and the first force steering member 22A from a front elevation view. The first vertebral anchor 18A, also described as an anchor arm, is adapted to be fixed, and provides means for fixation, to a third vertebra 26C (Figure 1). As described above, the first vertebral anchor 18A is fixed to a part of the spine 24 (Figure 1) that has an abnormal curvature that needs correction.

The first and second vertebral anchors 18A, 18B are optionally substantially similar, and therefore

15 various elements of both first and second vertebral anchors 18A, 18B are described together with the first vertebral anchor 18A, where when mentioned, elements of the first vertebral anchor 18A are designated with reference numbers followed by an "A" and similar elements of the Second vertebral anchor 18B are designated with similar reference numbers followed by a "B".

The first vertebral anchor 18A includes an arm 250A and a head 252A. In some embodiments, arm 250A extends from head 252A to a terminal end 254A and is generally arranged perpendicular to head 252A. The arm 250A is optionally rotatable with respect to the head 252B and is adapted to extend through a part of the third vertebra 26C, for example, from one side of the spine 24 to an opposite side of the spine 24. For example, the first vertebral anchor 18A is fixed to the third vertebra

25 26C so that the arm 250A extends through the third vertebra 26C through a hole or recessed part in the spinous processes (not shown) of the third vertebra 26C.

The head 252A is adapted, or otherwise structured, to be fixed to a part of the third vertebra 26C, such as a pedicle of the third vertebra 26C. The head 252A optionally includes and / or is adapted to work together with any of various structures capable of engaging with the third vertebra 26C. For example, the first vertebral anchor 18A optionally includes a pedicle screw 256A fixed through the head 252A to a pedicle of the third vertebra 26C.

The first force steering member 22A is fixed to the first vertebral anchor 18A in an appropriate location

35 at the first vertebral anchor 18A. For example, in some embodiments the first force steering member 22A is fixed to the first vertebral anchor 18A at least at the terminal end 254A of the arm 250A so that the first force steering member 22A extends from the terminal end 254A of the 250A arm

Additional examples of vertebral anchors (such as those described as "implants") according to some embodiments of the system 10 are described in US Application No. 11 / 196,952, filed on August 3, 2005 and entitled DEVICE AND METHOD FOR CORRECTING A SPINAL DEFORMITY, as well as 12 / 134,058, filed on June 5, 2008 and entitled MEDICAL DEVICE AND METHOD TO CORRECT DEFORMITY.

Figures 14a and 14b show the first adjustment mechanism 20A, where Figure 14b shows the first

45 adjustment mechanism 20A with a part removed to illustrate internal elements thereof. In some embodiments, the first adjustment mechanism 20A provides means for attaching the first force steering member 22A to the bar 12. In some embodiments, the first adjustment mechanism 20A, also described as a tensioner or coupler, is further adapted to adjust, and provide means for adjusting, a length of the first force steering member 22A. The first and second adjustment mechanisms 20A, 20B are optionally substantially similar. Therefore, various elements of both first and second adjustment mechanisms 20A, 20B are described together with the first adjustment mechanism 20A, where elements of the first adjustment mechanism 20A are designated with reference numbers followed by an "A" and elements Similar of the second adjustment mechanism 20B are designated with the same reference numbers followed by a "B".

In some embodiments, the first adjustment mechanism 20A includes a reel 260A, a circumferential sprocket 262A surrounding the reel 260A, a vertical cogwheel 264A in contact with the circumferential cogwheel 262A, a drive head 268A and a housing 270A .

The reel 260A, as well as the circumferential sprocket 260A and the vertical sprocket 264A are kept at least partially inside the housing 270A. In turn, the housing 270A is adapted to be attached to the bar 12. For example, the housing 270A optionally forms a central light through which it can be accommodated to the bar 12. At the time of insertion of the bar 12 a Through the central light, the housing 270A is adapted to be held on the bar 12.

In some embodiments, the housing 270A incorporates a "clam shell" design (for example, a first part fixed so that it can be adjusted to a second part) adapted to tighten on the bar 12 (for example, using one or more fixers). Therefore, in some embodiments, the first adjustment mechanism 20A is substantially fixed with respect to the bar 12. In other embodiments, however, the first adjustment mechanism 20A is mobile with respect to the bar 12, for example being capable of turning around bar 12.

5 The first force steering member 22A is attached or fixed to the reel 260A and passes out of the housing 270A through an opening of appropriate size in the housing 270A. The drive of the vertical sprocket 264A by the drive head 266A rotates the circumferential sprocket 262A, which in turn spins the reel 260A, thus winding (or unwinding, depending on the direction in which it is made turn reel 260A) to the first force steering member 22A around reel 260A. Rotation of

10 reel 260A in the appropriate direction draws the first force steering member 22A towards the first adjustment mechanism 20A, pulling the first vertebral anchor 18A (Figure 13) towards the first adjustment mechanism 20A according to some correction methods of a spine defect.

Additional examples of adjustment members (also those described as "adjustment mechanisms"), in accordance with

15 some embodiments of system 10 are described in US Application No. 11 / 196,952, filed on August 3, 2005 and entitled DEVICE AND METHOD FOR CORRECTING A SPINAL DEFORMITY, as well as 12 / 134,058, filed on June 5, 2008 and entitled MEDICAL DEVICE AND METHOD TO CORRECT DEFORMITY.

As shown in Figures 13 and 14, the first and second force steering members 22A, 22B are

20 optionally substantially similar, and therefore various elements of both first and second force steering members 22A, 22B are described together with the first force steering member 22A, where elements of the first force steering member 22A are designate with reference numbers followed by an "A" and similar elements of the second force steering member 22B are designated with similar reference numbers followed by a "B".

In some embodiments, the first force steering member 22A is substantially flexible so that the first force steering member 22A is capable of pivoting in multiple directions and / or being wound or wound, for example. Flexible materials suitable for forming the first force steering member 22A include wire and stranded cables, monofilament polymeric materials, polymeric materials

30 multifilament, carbon fibers or multifilament ceramics, and others. In some embodiments, the first force steering member 22A is formed of a stainless steel or titanium wire or wire, although various materials are contemplated.

The first force steering member 22A, also described as a connector or cable, is adapted to

35 fixed to the first vertebral anchor 18A and the first adjustment member 20A, the force steering member 22A defining an effective length between the first adjustment mechanism 20A and the first vertebral anchor 18A, and thus the bar 12 (although, In some embodiments, the first force steering member 22A is fixed directly to the bar 12). As described, in some embodiments, the first adjustment mechanism 20A is adapted to modify, and provides means to modify, the effective length of the steering member of

40 force 22A. The first force steering member 22A has a body 280A and extends from a first end 282A to a second end 284A.

Figure 1 shows the assembled system 10. In some embodiments, the assembly of the system 10 includes attaching the first and second force steering members 22A, 22B to the first and second vertebral anchors 18A, 45 18B, respectively. The first and second force steering members 22A, 22B are also fixed to the first and second adjustment mechanisms 20A, 20B. The first and second adjustment mechanisms 20A, 20B are fixed to bar 12. The first and second bar anchors 14A, 14B are fixed to the first and second vertebrae 26A, 26B, respectively. The bar 12 is housed in the first and second bar anchors 14A, 14B to fix the bar 12 against lateral translation with respect to the spine 24. The first and second anchors

50 vertebrates 18A, 18B are fixed to the third and fourth vertebrae 26C, 26D. At the time of assembly of the system 10, the first and second adjustment mechanisms 20A, 20B are adjusted as desired to pull the first and second vertebral anchors 18A, 18B towards the first and second adjustment mechanisms 20A, 20B and, of this mode, bar 12.

55 The first force steering member 22A is assembled to the first vertebral anchor 18A by fixing the first end 282A of the first force steering member 22A to the first vertebral anchor 18A near the terminal end 254A thereof. In some embodiments, the first force steering member 22A is fixed at the terminal end 254A of the first vertebral anchor 18A, and extends along at least a portion of the arm 250A to the head 252A, although the first steering member of force 22A is attached at any location along

60 of arm 250A and / or head 252A of the first vertebral anchor 18A as appropriate. The first force steering member 22A can be fixed to the first vertebral anchor 18A by various methods, including welding, adhesives, ligation and / or screw fixing, for example.

The second force steering member 22B and the second vertebral anchor 18B are optionally fixed or connected together using similar strategies.

As described above, the first force steering member 22A extends to the first adjustment mechanism 20A, enters the housing 250A and is wound around the reel 260A, thereby coupling the first adjustment mechanism 20A to the first vertebral anchor 18A as well as to bar 12. In some embodiments, the first force steering member 22A is fixed to reel 260A by welding, fixing with

5 screws, adhesives, and / or is sufficiently wrapped around reel 260A for frictional retention of the first force steering member 22A on reel 260A.

The second force steering member 22A and the second adjustment mechanism 20B are optionally fixed.

or connected together using similar strategies.

The bar 12 is housed by the housings 40, 200 of the first and second bar anchors 14A, 14B, respectively. Elements of the first and second bar anchors 14A, 14B are selected to limit pitch, yaw, warp and axial slide of bar 12 as desired.

15 The bar 12 is fixed against the lateral translation with respect to the longitudinal axis of the spine 14 by fixing the first and second bar anchors 14A, 14B to at least the first and second vertebrae 26A, 26B, respectively. The first rod anchor 14A is fixed to at least the first vertebra 26A, for example by screwing the first rod anchor 14A to the first vertebra 26A (for example, on or near the transverse processes) using one or more pedicle screws. The second bar anchor 14B is fixed analogously to at least the second vertebra 26B. The first bar anchor 14A and / or the second bar anchor 14B is optionally fixed to multiple vertebrae 26 for improved stability.

In some embodiments, the bar 12 is connected by the bar anchors 14A, 14B to the transverse process on the left side of the spine 24 and is capable of sliding axially with respect to the first and / or second

25 bar anchors 14A, 14B. In other embodiments, the bar 12 is joined by the bar anchors 14A, 14B to the right side of the spine 24, on different sides of the spine 24 (for example, the first bar anchor 14A in the left loop and the second bar anchor 14B on the right side), or along the midline of the spine 24. In other embodiments, the bar 12 is of adjustable length to compensate for changes in spine length 24. Regardless, the interaction between the bar 12 and the first and second bar anchors 14A, 14B helps facilitate growth and a more natural movement of the spine 24.

Figures 15a, 15b and 15c show various stop elements 286 to limit the sliding or axial translation of the bar 12 with respect to a bar anchor, such as the first bar anchor 14A. Generally, the sliding of the bar 12 is a particular axial direction is substantially limited, or stopped, when a

35 stop element 286 engages, or stops with an adjacent bar anchor 14.

As shown in Figure 15a, the bar 12 optionally includes a narrowed part 286a housed in the first bar anchor 14A with wider wider adjacent parts 286b of the bar 12 limiting the axial sliding of the bar 12. As shown, Although axial sliding of the bar 12 is substantially prevented by locating the stopper elements 286 adjacent to the first bar anchor 14A, some tolerance, or play, is still allowed, as appropriate in the fit between the widest parts 286b of the bar 12 and the first bar anchor 14A.

As shown in Figure 15b, the system 10 optionally includes stops 286c, or collars, which are

45 fitted on the bar 12 adjacent to the first bar anchor 14A to substantially limit the axial sliding of the bar 12 within the first bar anchor 14A. In some embodiments, the stops 286c are metal or polymeric collars set on the bar 12, although various designs and fixing methods are employed, as desired. As shown, although the axial sliding of the bar 12 is substantially impeded with respect to the first bar anchor 14A, there is still some limited play or stop as appropriate in the fit between the bar 12 and the stops 286c.

As shown in Fig. 15c, the system 10 optionally uses both a stop 286c and a narrowed portion 286a with a wider part 286b to limit the axial sliding of the bar 12 with respect to the first bar anchor 14A within a range of desired movement. For example, as shown in the

Figure 15c, the stop 286c is located towards one end of the bar 12 on one side of the first bar anchor 14A and the widest part 286b is located on the other side of the first bar anchor 14A with a desired gap between the stop 286c and the widest part 286b. Any combination of stop elements 286 and separation is implemented as appropriate.

Figure 16 is a schematic view of a system 10A similar to that of Figure 1, where Figure 16 illustrates varying degrees of freedom of the bar 12 in the first and second bar anchors 14A, 14B, in accordance with some embodiments. As shown, the system 10A also includes a third vertebral anchor 18C fixed to a fifth vertebra 26D. The third vertebral anchor is substantially similar to the first and / or second vertebral anchors 18A, 18B. The system 10 also optionally includes a third corresponding force steering member 65C 22C, for example, a cable or wire, and a third adjustment mechanism 20C. Although adjustment mechanisms 20 have been described which include means for adjusting the effective length of the steering members

of force 22, in some embodiments one or more of the adjustment mechanisms 20 act as a means for attaching a force steering member corresponding to the bar 12 without incorporating said adjustment elements. For example, the third adjustment mechanism 20C, or any of the adjustment mechanisms described herein, is optionally a clip or fixing means for attaching the force steering member 22C to the bar

5 12 (for example, a clamp or staple).

The bar 12 is bent (for example, as shown in Figure 3) and, as indicated by the directional arrows, it is free to change pitch, yaw and warp, as well as to slide axially along the axis longitudinal X in the first bar anchor 14A (and therefore, in the first pivot point P1) and is free to change pitch and yaw in the second bar anchor 14B while relative changes of warping and axial sliding are substantially limited or substantially impeded in the second bar anchor 14B (and, therefore, in the second pivot point P2). In some embodiments, collars 288A or other abutment elements (such as those described above) are located in bar 12 (eg, crimped to bar 12) on either side of the second bar anchor 14B to inhibit the movement of

15 sliding the bar 12. In turn, a stop member 288B (such as one of those described above) is located near one end of the bar 12 to help prevent the bar 12 from sliding out of the first anchor of bar 14A.

The interaction between the vertebral anchors 18A, 18B, the adjustment mechanisms 20A, 20B and, in particular, the flexible nature of their respective coupling by using the force steering members 22A, 22B allows the system 10 to move from dynamically with the spine 24, while exerting and / or maintaining a corrective force (for example, lateral and rotational forces) on the third and fourth vertebrae 26C, 26D. In other words, the system 10 is semi-constrained, providing a lateral and rotational anchor point while facilitating at least some degree of natural movement in the spine 24.

In addition, by limiting the rotation, or warping, of the bar 12, the curvature in the bar 12 is oriented and maintained in a desired rotational position. Maintaining rotational orientation at one end (i.e., at the second bar anchor 14B) is useful, for example, to help ensure that the curvature or shape of the bar 12 follows consistently or appropriately tracks otherwise. a desired curvature of a spine 24. Freedom of rotation at the other end of the bar 12 (ie, at the first bar anchor 14A), however, still allows the spine 24 to have a more natural movement while corrective forces are being applied.

Therefore, according to various embodiments, the spine 24 (and, therefore, the person) is capable of

35 rotate, bend back and forth, and bend forward and backward more naturally while corrective forces are being applied to the spine 24. In some embodiments, the effective lengths of the force steering members 22A, 22B they adjust (for example, periodically or all at the same time), bringing the spine to a natural alignment, while the system 10 continues to facilitate a more natural movement of the spine 24 (for example, turning and bending forward and back and forth) due to the freedom of movement provided by system 10.

FIG. 17 is a schematic view of a system 10B illustrating varying degrees of freedom of the rod 112 in the first rod anchor 14A and a second rod anchor 290 substantially similar to the first rod anchor 14A, in accordance with some other embodiments of the system 10. With system 10B, bar 112 is

45 substantially straight (figure 4) and, as indicated by the directional arrows, it is free to change pitch, yaw and warp, as well as to slide axially along the longitudinal axis X, in each of the first and second anchors bar 14A, 290.

In some embodiments, each of the first and second bar anchors 14A, 290 generally shown in Figure 16 are substantially the same as the first bar anchor 14A shown in Figures 5a and 5b, for example. In other embodiments, each of the first and second bar anchors 14A, 290 are substantially the same as the first bar anchor 114A shown in Figures 7 and 8, although any combination of the anchoring elements described above together with any one is contemplated. of bar anchors 14A, 114A, 14B.

The bar 112 also optionally includes stop elements 300, such as the stop elements 286 described above, to help prevent the bar 112 from sliding out of the first and second bar anchors 14A, 290. Thus, the bar 112 is able to slide axially, along the longitudinal axis X (Figure 4) until one of the stop elements 300 contacts one of the first and second bar anchors 14A, 290. Again, the system 10B provides dynamic adjustment and movement with the spine, while exerting a corrective force (for example, translational and rotational forces) on the vertebrae 26 (for example, the third and fourth vertebrae 24C, 24D).

Figures 18 and 19 show systems 10C, 10D, respectively, showing variations in constriction of

65 the axial bar according to some embodiments. The systems 10C, 10D are each shown including a first bar anchor 360 and a second bar anchor 370 incorporating elements of any of the anchors described above. The axial arrows indicate freedom of movement of the associated bars, although an indication of degrees of freedom of pitch, yaw and warp at the anchors 360, 370 are left from Figures 18 and 19 to facilitate illustration. Various degrees of freedom are incorporated into anchors 360, 370 as appropriate.

5 As shown in Figure 18, the system 10C includes a bar 375 (for example, similar to bar 12A) that includes a bar adjustment mechanism 376 (for example, similar to the bar adjustment mechanism 39), a first stop element 380A, a second stop element 380B, and a third stop element 380C, the stop elements 380A, 380B, 380C being fixed to and / or formed with the bar 375 (for example, similar to the elements of stoppers that are similar to any of the stopper elements 286 described above).

The bar 375 is substantially constrained against the axial sliding by the second and third stop elements 380B, 380C in the second bar anchor 370 and some axial sliding, or axial translation, is allowed outwards away from the first stop element 380A. In some embodiments, the stop elements 286 and the

15 first and second bar anchors 360, 370 provide means to impose a spreading force on the spine 24 and / or to limit compression of the spine 24 along one or more sides of the spine 24 (by example, left, right, front and / or back sides).

In some embodiments, the bar adjustment mechanism 376 is used to apply a stretching force by expanding an effective length of the bar 375 so that the first and second stop elements 380A, 380B are engaged with the first and second bar anchors. 360, 370 resulting in a compression force on the bar 375 that the bar 375 resists substantially rigid. The compression force on the bar 375, in turn, results in an elongation or strain force on one side of the spine 24 to which the anchors 360, 370 of the system 10C are coupled. In addition, the stop elements additionally or as

Alternative 25 provide a limit to the compression of the spine 24 on the first side of the spine 24 by limiting the relative movement of the anchors 36, 370 towards each other on the bar 375.

Although the bar 375 of the system 10C is placed under a compression load, the bar 375 is able to move axially in a first direction, for example, to allow for additional strain and / or natural movement

-

 for example, so that the spine 24 (and, therefore, the person) is able to rotate, bend on either side, and bend forward and backward more naturally while stretching forces are being applied to the spine 24. In turn, the axial movement of the bar 375 in a second direction generally opposite to the first direction is limited (for example, thereby limiting compression of the spine 24 beyond the established axial limit by the stop elements 286). Also, although the

System 10C has been described as applying a strain force and / or a compression limit to one side of the spine 24, in other embodiments a strain force is applied to both sides of the spine 24, to an anterior side. of the spine 24, to a posterior side of the spine 24, or combinations thereof.

As shown in Figure 19, the system 10D includes a bar 400 (for example, similar to bar 12A) that includes a bar adjustment mechanism 402 (for example, similar to the bar adjustment mechanism 39), a first stop element 410A and a second stop element 410B, the stop elements 410A, 410B being fixed to and / or formed with the bar 400 (for example, similar to any of the stop elements 286 described above). The bar 400 is substantially constrained against axial sliding and / or expansion towards

45 out of the first and second abutment elements 410A, 410B, providing the abutment elements 41A, 410B providing means to impose a compressive force on the spine 24 and / or to limit the distention of the spine 24 along one or more sides of the spine 24 (for example, left, right, anterior and / or posterior sides). In some embodiments, the bar adjustment mechanism 402 is used to apply a contraction or tension force on the spine to which the system 10D is coupled by contracting or cutting the bar 400 using the adjustment mechanism 402 so that the first and second stopper elements 410A, 410B mesh with the first and second rod anchors 360, 370 to apply a compression force to the spine (not shown).

Although the bar 400 of the 10D system is placed under a tensile load, the bar 400 is able to move

55 axially in a first direction, for example, to allow additional compression of the spine 24 (and, therefore, the person) is able to rotate, bend on either side, and bend forward and backward of more naturally, while compression forces are being applied to the spine 24. The axial movement of the bar 400 remains substantially limited in a second direction generally opposite to the first direction, for example, limiting the spine distension 24 more beyond the axial limit established by the stop elements 286. In addition, although the system 10D is described as applying a compression force and / or strain limit to one side of the spine 24, in other embodiments a tensile force or compression is applied to both sides of the spine 24, to a front side of the spine 24, to a back side of the spine 24, or combination It is the same. In further embodiments, the 10D system may apply a compression force and / or a strain limit to one side of the

65 spine 24, while system 10C applies a strain and / or compression limit to the opposite side of the spine 24.

In view of the above, the systems according to the various embodiments provided herein help minimize a series of anchor points used for correction, facilitate the use of straight or contoured bars, and / or help promote a movement. more natural, physiological of the spine 24 during or after the correction of the deformity.

Claims (14)

1. A spine anchoring system (10) comprising: 5 a bar (12) adapted to extend along a spine of a patient; and a bar anchor (14B) adapted to be fixed to a vertebra of the spine, the bar anchor (14B) adapted to accommodate the bar (12) so that the bar (12) is fixed against substantial lateral translation with respect to the bar anchor (14B), characterized in that the bar (12) is allowed to slide axially with respect to the bar anchor (14B) through a pivot point (P2) and to change pitch and yaw around the pivot point (P2) while substantially limiting the warping of the bar (12) with respect to the bar anchor (14B). 2. The system (10) of claim 1, wherein the bar anchor (14B) comprises: 15 a housing (200) forming a receptacle part (202) having a substantially concave internal surface (210); and a sleeve (204) housing the bar (12) so that it can slide and having a substantially convex coupling surface (212) adapted to engage with the concave inner surface (210) of the receptacle part (202) of so that the sleeve (204) is adapted to rotate with respect to the receptacle part (202) to change pitch and yaw. 3. The system (10) of claim 2, wherein the bar (12) defines a feed element and the sleeve (204) forms a feed cavity that houses so that it can slide to the feed element of the bar (12) to substantially limit the warping of the bar (12) in the sleeve (204), the sleeve (204) having a surface of 25 substantially convex coupling adapted to engage with the concave inner surface (210) of the receptacle part (202) so that the sleeve (204) is capable of changing pitch and yaw with respect to the receptacle part (202) .

Four.

 The system (10) of any one of claims 2 or 3, wherein the receptacle part (202) and sleeve (204) are adapted to substantially inhibit warping with respect to each other.

5.

 The system (10) of any one of claims 2 to 4, wherein the receptacle part (202) has a protuberance (216) extending inwardly from the concave inner surface and the sleeve (204) has a groove circumferential (218) on the convex coupling surface that engages with the protuberance (216) in the

35 concave inner surface of the receptacle part (202) so that the sleeve (204) is adapted to rotate with respect to the receptacle part (202) to change pitch and yaw with respect to the receptacle part (202 ) while substantially preventing it from changing its warping with respect to the receptacle part (202).

6.

 The system (10) of any one of claims 1 to 5, wherein the bar anchor (14B) is further adapted to limit the warping of the bar (12) with respect to the bar anchor (14B) to a predefined interval.

7.

 The system (10) of any one of claims 1 to 6, wherein the bar anchor (14B) is adapted,

furthermore, to limit the pitch of the bar (12) with respect to the bar anchor (14B) at a predefined interval. Four. Five

8.

 The system (10) of any one of claims 1 to 7, wherein the bar anchor (14B) is further adapted to limit the yaw of the bar (12) with respect to the bar anchor (14B) to a predefined interval.

9.

 The system (10) of any one of claims 1 to 8, wherein the bar anchor (14B) is adapted to limit the axial sliding of the bar (12) with respect to the bar anchor (14B) at an interval predefined

10.

 The system (10) of any one of claims 1 to 9, further comprising:

an additional bar anchor (14A, 114A) adapted to attach to another vertebra and to accommodate a second 55 end of the bar (12); and a force steering member (22A) coupled between the bar (12) and the deformity of the spine; wherein the bar anchors are adapted to resist lateral translation of the bar (12) with respect to the spine and to allow a longitudinal axis of the bar (12) to change from at least one pitch and one yaw. 11. The system (10) of any one of claims 1 to 9, further comprising: an additional bar anchor (14A, 114A) adapted to be fixed to another vertebra, the additional bar anchor (14A, 114A) housing the bar (12) so that the bar (12) is fixed against substantial lateral translation with respect to 65 the additional bar anchor (14A, 114A) and be allowed to change at least pitch and yaw around an associated pivot point (P1); a vertebral anchor (18A) adapted to be fixed to an additional vertebra (26C); an adjustment mechanism (20A); and a force steering member (22A) coupled to the vertebral anchor (18A) and the rod (12), the force steering member (22A) defining an effective length between the vertebral anchor (18A) and the rod (12) , the adjustment mechanism (20A) being adapted to modify the effective length of the steering member of 5 force (22A). 12. The system (10) of claims 10 or 11, wherein the additional bar anchor (14A, 114A) is further adapted to allow warping of the bar (12) around the pivot point (P1) associated. The system (10) of any one of claims 10 to 12, wherein the bar (12) defines an advance element and the additional bar anchor (14A, 114A) comprises: a housing that forms a receptacle part (202) having a substantially concave internal surface; Y 15 a sleeve (204) that forms an advance cavity that houses so that the advance element of the bar (12) can slide to substantially inhibit the warping of the bar (12) in the sleeve (204), the sleeve having (204) a substantially convex coupling surface adapted to engage with the concave inner surface of the receptacle part (202) so that the sleeve (204) is adapted to rotate with respect to the receptacle part (202) to change from nodding and yaw. 14. The system (10) of claim 13, wherein the additional bar anchor (14A, 114A) further comprises a projection between the receptacle part (202) and the sleeve (204), including the sleeve (204) a circumferential groove (218) housing the projection, so that the sleeve (204) is able to change pitch and yaw with respect to the receptacle part (202) and is substantially prevented from changing the warping with 25 with respect to the receptacle part (202). 15. The system (10) of any one of claims 1 to 9, further comprising: means for attaching the bar (12) to another vertebra (26B) of a spine, so that the bar (12) is 30 capable of changing at least pitch and yaw around an associated pivot point (P1) defined by the means for fixing the bar (12) to the other vertebra (26B); means for anchoring to an additional vertebra (26C); a connector coupled to the bar (12) and the means for anchoring to the additional vertebra (26C); and means for adjusting an effective connector length.